Chromatic Chronometer Assembly Instructions
PCB Arc Segment Layout Reference A. GND, DATA, and +3V3 (Ground, data, and power connections between boards) B. 4-prong section for LED mounting C. Indicator for LED orientation D. Solder mount location for 0.1uF capacitors E. Microcontroller location for master segment F. Location for light sensor G. Location for 10k resistors H. Location for 22pF capacitors I. Location for 32.768 kHz clock crystal J. Location of buttons K. PIC (Microcontroller) bypass location L. Voltage Regulator location and 3 solder contacts M. Solder mount location for 0.1uF capacitors N. Power supply cord solder location Step-by-step Build Instructions 1.1.1. Start by taking an inventory of the components. Make sure you have everything described in the Kit Contents section. 1.1.2. Take the 6 PCB segments and assemble them in a circle, face up. 1.1.3. Using painting tape or other tape that is easily removed without leaving a residue, connect the edges of the PCBs together. This will make it easier to move and solder together the PCBs in future steps. 1.1.4. Set aside the PCBs and, over a safe cutting surface, strip the insulation from the solid-core wire. While several methods will work for this step, I have had success using a straight razor on a cutting board and gently slicing away one side of the insulation. 1.1.5. With the insulation removed, cut the wire into 18 small pieces, each approximately 1/4" long. This will serve as additional support for the soldered connections to provide a stronger, more rigid connection between your PCB sections. 1.1.6. Flip the taped PCBs face-down. 1.1.7. Each PCB has three connection points to the neighboring PCB labeled +3V3, DATA, and GND. On each connection, place a 1/4" wire segment and solder it in place on both PCBs. 1.1.8. Repeat this process until all connection points have been joined with solder and wire. 1.1.9. Remove the tape from the face of the PCB ring. The ring should stay together of its own accord. 1.1.10. Flip the PCB ring face-up and identify the LED solder pads on the outside of the ring. 1.1.11. Each LED has four pins that will be soldered to its pads (red circles). Take careful note that one corner of each LED has a special marking. This marking is used for orienting the LED correctly on the PCBs. The marked corner of the LED must align with the marked corner of the silkscreen on the PCB (blue circle). 1.1.12. Solder each of the 60 LEDs to their locations on the PCB. 1.1.13. Beneath each LED, solder a 0.1uF capacitor. The picture above depicts the capacitors partially installed. 1.1.14. Flip the ring face-down and select one of the six segments on which to solder the microcontroller. This segment will be known as the master segment. The remaining five segments will be referred to as slave segments. When soldering the microcontroller chip, make sure the "dot" (the indentation) on the top or corner of the chip aligns to the curved segment of the silkscreen (white printing). In the picture above, the dot is on the top of the chip (i.e. facing outwards from the ring). 1.1.15. ''Install the optical sensor on face of the ''master segment. The component leads should protrude through the back of the segment to where the optical sensor symbol is. 1.1.16. ''On the back of the ''master segment, solder the leads of the optical sensor in place. 1.1.17. ''Clip the leads of the optical sensor where they meet the solder joint. 1.1.18. Solder two 10k resistors to their respective pads on the 'master segment. These pads are identified by the silkscreen label "10k" and are located just below the light sensor and just above the microcontroller. The resistors can be distinguished from the capacitors because they are black on one side and read "103" in extremely tiny writing. They are found in the small clear bag with the buttons. '' '' ''1.1.19. ''Solder two 22pF capacitors to their respective pads on the ''master segment''. These pads are identified by the silkscreen label "22pF" and are located to the left of the microcontroller. The capacitors are found in the anti-static (grey) bag with the microcontroller. They are used in oscillating the crystal during the clock's operation. ''1.1.20. ''Locate the 32.768 kHz crystal. Using tweezers to hold the leads where they meet the crystal's body, bend the leads at a 90-degree angle, being careful not to pull the leads from the crystal's case. '''Pulling the leads or bending them directly without tweezers protecting the body may cause cracks in the glass hermetic seal of the crystal which may cause component failure. With the leads bent, place them into the crystal's through-holes on the master segment between the 22pF capacitors and aside the microcontroller. Solder them in place on the front face of the ring and clip the leads. (This is similar to the installation of the optical sensor, but on the back of the ring rather than the front.) 1.1.21. ''Solder the three buttons on the ''master segment ''to the locations labeled NEXT, PREV, and SET. 1.1.22. ' 'On each of the five ''slave segments, locate the pads labeled PIC bypass near the right edge of the segment. Place enough solder on these pads to bridge the pads together. This enables the data signal to proceed through the segments without the need of additional microcontrollers. (The type of microcontroller installed is called a PIC.) Do not bridge the bypass of the master segment, as this segment already has the PIC microcontroller installed. 1.1.23. ''Select a segment to house the voltage regulator. This can be either the ''master segment or any of the slave segments. It is generally preferable to choose a segment opposite the master segment because the master segment lies near the top of the clock (12:00, by virtue of having the microcontroller installed on it) while the power cord is likely to be draped below the clock when in use. The picture above illustrates this placement . 1.1.24. ''Solder the voltage regulator into place. On either side of the voltage regulator, solder a 0.1uF capacitor. NOTE: These are the same capacitors you used under each of the LEDs and are found in the long ribbon of capacitors in the bag with the LEDs. ''1.1.25. ''Most power supplies have a connector at the end of their cords, like the one shown above. With the power supply unplugged, cut the connector off of the cord and separate the two wires for a couples inches from the end of the cord. Strip the insulation from the end of the wires. REMINDER: The clock supports a power supply that delivers between 4 volts and 6 volts, optimally with 1 amp of current. This can often be found in the form of an old mobile phone charger. If you do not have an unused power supply that fits the description, searching eBay or other supplier for ''wall power adapter 5v 1a (and sorting by cost) will generally yield an option for less than $2.50, including shipping. 1.1.26. Locate the power inputs above the voltage regulator, labeled 4V to 6V and GND. Use a multimeter to determine which wire of the power supply is voltage and which is ground with the power supply is plugged in. When the multimeter's red probe is on the voltage wire and the black probe is on the ground wire, the multimeter display will read close to 5 volts. If they are reversed, the display will be close to -5 volts. Unplug the power supply and solder the power supply's wires into the inputs above the voltage regulator. After soldering, it may be helpful to glue the wires into place with a hot glue gun to prevent them from moving about or being yanked out. ' '